I was talking to a friend who formerly worked at the EPA about quenching sodium metal at the end of a reaction and his initial response was, "you aren't allowed to do that, EPA doesn't let you treat waste like that." LIke all good friends, he dug into the issue and sent me this link, https://rcrapublic.epa.gov/files/14618.pdf, highlighting this paragraph (he acknowledged that his initial response was incorrect):

'If the waste is being treated on-site and the treatment residue is destined to be land disposed, the generator still has responsibilities under the land disposal restrictions (LDR) program.  The LDRs require that hazardous waste must be treated by a specified method or to a specified constituent concentration level before it (or its residue) may be placed in the land.  The generator must know the treatment standard applicable to his/her waste and either treat to meet the treatment standard or send it to a treater to do so.  Generators who treat waste on-site to remove a hazardous characteristic must prepare a waste analysis plan if treatment occurs in units that do not require a RCRA permit (see 40 CFR 262.34(a)(4) for LQGs, and 40 CFR 262.34(d)(4) forSQGs).  In addition, there are some generator paperwork requirements associated with the LDRs(40 CFR268.7(a))."